Lugging at speed/No power at WOT

[ArdWrknTrk]

Honest answer:

Yeah, and so does "everybody". It's kinda why I'm not a huge 302 fan (or heck, the freaking LS!) for the most part... been done so many times that "special" doesn't exist any more. Not that (in both cases here) it's bad, or doesn't work, or isn't a good option for some people, but it's not my style or desire. I enjoy building things that aren't the usual trendy thing.

No offense intended... I get flack like this on pretty much every build I do for similar "it would be easier if you did X like everybody else" rationales. Not just trucks... computer builds and even my choice of homes (and how I chose to furnish/adorn it) has seen such at one point or another. I'm weird!

If the electronics were already stripped or there was some reason that it absolutely wouldn't work... then fine, back to the stone age we go. Although at that point, I'd probably be saving up for an offy intake and 4 barreling it. I've read it can match a 351 if built right (4 barrel + better flowing exhaust) while keeping most of the 300's fuel economy. This isn't merely a form of essential transportation, so I'm not inclined to do something just to make it run...

I understand, and I'm not giving you "flack"

We here are all about 'Make it Yours', and do our best to be supportive of that position.

But the feedback system was sketchy when it was new, and NOS parts are challenging to find.

Many convert to the DSII system, and some -that are doing it on a shoestring- go with the path of least resistance.

Oh, and I want to correct my previous post.

The $65 HEI I was looking at was for the car I-6, the one that fits the 240/300 is $110.

Do you have the catch code from your original module?

Maybe one of us can turn one up?

David seems especially good at that, and he has a deep knowledge of these engines.

[ratdude747]

I understand, and I'm not giving you "flack"

We here are all about 'Make it Yours', and do our best to be supportive of that position.

But the feedback system was sketchy when it was new, and NOS parts are challenging to find.

Many convert to the DSII system, and some -that are doing it on a shoestring- go with the path of least resistance.

Oh, and I want to correct my previous post.

The $65 HEI I was looking at was for the car I-6, the one that fits the 240/300 is $110.

Do you have the catch code from your original module?

Maybe one of us can turn one up?

David seems especially good at that, and he has a deep knowledge of these engines.

I know a lot of people do DSII... again, one "hobby" of mine is trying to make rejected "overcomplicated" technology work. My AV rack at home has S-VHS, Laserdisc, and HD-DVD included (and a beta VCR in the garage) if you want another example.

I'm not going condemn the ECU until I have a verified working O2 sensor...

[ArdWrknTrk]

I know a lot of people do DSII... again, one "hobby" of mine is trying to make rejected "overcomplicated" technology work. My AV rack at home has S-VHS, Laserdisc, and HD-DVD included (and a beta VCR in the garage) if you want another example.

I'm not going condemn the ECU until I have a verified working O2 sensor...

You sound like you'd really enjoy the Technology Connections YouTube channel.

[ratdude747]

You sound like you'd really enjoy the Technology Connections YouTube channel.

"Traded" the bad ECU for the carb off that truck and one of the upstream O2's off the explorer I got the pigtail from. The carb is for parts; it's a bit rough (lots of loose screws the intake was full of water and rusted the bottom of the throttle plate) and has no TV cable provisions.

The new O2 sensor is working and at idle I'm getting 0.88V between the O2 signal and ground (RICH!) at the ECU plug... but KOER is still giving me 23 and 41. Something isn't happy with the ECU; Almost seems like an analog input issue (since both faults are for analog sensors), but I'll need to do more debugging on the ECU board itself to see.

The 1986 and 1984 ECUs had very different packaging and board designs; the 1986 was cased in cast aluminum (better heatsinking) while the 1984 is cased in stamped sheet metal. The 1986 was OEM'd by motorola, while the 1984 one didn't have any OEM marks that I remember (edit: it's probably OEM'd by toshiba, as most of the chips are made by them. They and motorola were the 2nd sources for the Intel 8061 controller made specifically for EECIV, so this makes sense). Hence the different part numbers.

1984 ECU stickers:

[ratdude747]

"Traded" the bad ECU for the carb off that truck and one of the upstream O2's off the explorer I got the pigtail from. The carb is for parts; it's a bit rough (lots of loose screws the intake was full of water and rusted the bottom of the throttle plate) and has no TV cable provisions.

The new O2 sensor is working and at idle I'm getting 0.88V between the O2 signal and ground (RICH!) at the ECU plug... but KOER is still giving me 23 and 41. Something isn't happy with the ECU; Almost seems like an analog input issue (since both faults are for analog sensors), but I'll need to do more debugging on the ECU board itself to see.

The 1986 and 1984 ECUs had very different packaging and board designs; the 1986 was cased in cast aluminum (better heatsinking) while the 1984 is cased in stamped sheet metal. The 1986 was OEM'd by motorola, while the 1984 one didn't have any OEM marks that I remember (edit: it's probably OEM'd by toshiba, as most of the chips are made by them. They and motorola were the 2nd sources for the Intel 8061 controller made specifically for EECIV, so this makes sense). Hence the different part numbers.

1984 ECU stickers:

Pulled the board... did some reverse engineering.

Still no ID on the mystery chip... although I have a rough idea of what it does... and found an issue. The issue is that the chip is powered off the 5V supply inside the ECU (the V ref used by a lot of sensors), but is grounded through the O2 ground. Since the O2 ground isn't tied to the main ground any more (Unless the O2's case is internally bonded to the sensor ground), that chip isn't able to get power. I'll probe my O2 sensors to see what's up. If it isn't bonded, I'll need to jumper the heater ground to the sensor ground at the plug (for noise rejection reasons, the jumper needs to be as close to the sensor as possible, why a separate ground exists in the first place); if it is, then my trashed threads in the manifold are probably causing a weak connection, which is likely the issue I've been fighting all along. Yay helicoil... and/or I'll bond the grounds at the plug anyway. I don't like creating ground loops (again, signal noise reasons), but if that's what I need to ensure I have solid grounding, so be it.

Edit: Not case grounded. Looks like I have more harness work to do...

[grumpin]

Pulled the board... did some reverse engineering.

Still no ID on the mystery chip... although I have a rough idea of what it does... and found an issue. The issue is that the chip is powered off the 5V supply inside the ECU (the V ref used by a lot of sensors), but is grounded through the O2 ground. Since the O2 ground isn't tied to the main ground any more (Unless the O2's case is internally bonded to the sensor ground), that chip isn't able to get power. I'll probe my O2 sensors to see what's up. If it isn't bonded, I'll need to jumper the heater ground to the sensor ground at the plug (for noise rejection reasons, the jumper needs to be as close to the sensor as possible, why a separate ground exists in the first place); if it is, then my trashed threads in the manifold are probably causing a weak connection, which is likely the issue I've been fighting all along. Yay helicoil... and/or I'll bond the grounds at the plug anyway. I don't like creating ground loops (again, signal noise reasons), but if that's what I need to ensure I have solid grounding, so be it.

Edit: Not case grounded. Looks like I have more harness work to do...

Good find!

[ratdude747]

Good find!

We'll see...

In the mean time, I've hit another snare. went to unplug the O2, and it popped out of the manifold. No more good threads that the sensor can access :(

The good news is that repair kits exist. The bad news is they're wicked expensive. But I did find this:

https://www.ebay.com/itm/Helicoil-4833-Oxygen-Sensor-Thread-Repair-Kit-M-18-x-1-5/164233766665?epid=1368619882&hash=item263d186709:g:A7cAAOSwztRe2sAD&autorefresh=true

Threw an offer on it, but honestly I should probably pony up and nab it while I can. Edit: Found this: https://www.amazon.com/Thread-Kits-1218-500-Repair-Kit/dp/B0025PQITU. I get free 2-day shipping through my wife's prime account... If the offer fails, I'll hit that instead.

Beats replacing the manifold... that EGR tube is likely to be a PITA, and I'd have to redo the choke tubes again.

[85lebaront2]

We'll see...

In the mean time, I've hit another snare. went to unplug the O2, and it popped out of the manifold. No more good threads that the sensor can access :(

The good news is that repair kits exist. The bad news is they're wicked expensive. But I did find this:

https://www.ebay.com/itm/Helicoil-4833-Oxygen-Sensor-Thread-Repair-Kit-M-18-x-1-5/164233766665?epid=1368619882&hash=item263d186709:g:A7cAAOSwztRe2sAD&autorefresh=true

Threw an offer on it, but honestly I should probably pony up and nab it while I can. Edit: Found this: https://www.amazon.com/Thread-Kits-1218-500-Repair-Kit/dp/B0025PQITU. I get free 2-day shipping through my wife's prime account... If the offer fails, I'll hit that instead.

Beats replacing the manifold... that EGR tube is likely to be a PITA, and I'd have to redo the choke tubes again.

I've run into that on the 4.9L FBC and 1985-86 5.0L EFI engines, damn cast iron gets very weak after years of heat/cool cycles, Thread is same as a 14mm spark plug and can be Helicoiled.

[ratdude747]

I've run into that on the 4.9L FBC and 1985-86 5.0L EFI engines, damn cast iron gets very weak after years of heat/cool cycles, Thread is same as a 14mm spark plug and can be Helicoiled.

It's the same as M18x1.5 spark plugs. Which is what those kits are for.

The threads got messed up beyond what a thread chaser could fix when I replaced the O2 sensor last year. Tried tapping it, which didn't help... but there was one thread left that the stock type sensor could reach with the copper washer removed. That thread popped today.

---

Was able to set the sensor in hole and test it at least... getting around 1V at idle (not fully warmed up, so richer is normal?). Another KOER test still gives 23 and 41... Either the ECU has an internal issue I'm half helpless to fix without an ECU replacement, or I am doing something terribly wrong.

[ratdude747]

It's the same as M18x1.5 spark plugs. Which is what those kits are for.

The threads got messed up beyond what a thread chaser could fix when I replaced the O2 sensor last year. Tried tapping it, which didn't help... but there was one thread left that the stock type sensor could reach with the copper washer removed. That thread popped today.

---

Was able to set the sensor in hole and test it at least... getting around 1V at idle (not fully warmed up, so richer is normal?). Another KOER test still gives 23 and 41... Either the ECU has an internal issue I'm half helpless to fix without an ECU replacement, or I am doing something terribly wrong.

The plot thickens.

Poking around the calibration lists on the site (my cal sticker had faded to white when I got the truck, and was removed when I painted the valve cover).

From what I can tell, the correct ECU was one the "ZB" ones... mine is a "ZA" (a Z1A, to be exact), which only shows on the list as a 1985 part (number 440, the "ZB" is also listed as a valid number).

Very odd... either this ECU isn't original, or ford's cal lists are lying (or it's a weird transition between years build?)

Edit: Rockauto (via cardone) lists the ZA and ZB as the same thing... one common part, which they have in stock ($125 after core return).

Edit: From what I can see, the E5DZ 12A650-VB from 1986 (300 AOD RWD normal emissions, list #471) is also compatible to some degree. The only other different part on the list is the carb itself... and from what I see on my 1986 carb, there isn't much different.